Expert reaction to high levels of air pollution in England today

Issue date: 02 April 2014


Jo Barnes - Research Fellow in the Air Quality Management Resource Centre

UWE Bristol expert Jo Barnes is available to comment on the high levels of air pollution currently spreading across England, Jo is a Research Fellow in the Air Quality Management Resource Centre, at the University of the West of England.

Commenting on the pollution Jo said: “While the high levels of air pollution that we are seeing this week across England and Wales are a result of a combination of short-term meteorological factors and continental and Saharan sources, it is important to recognise that this is simply adding to and exacerbating existing long-term poor air quality experienced in many of our towns and cities much of the rest of the time.

“There are already more than 60% of UK local authorities with Air Quality Management Areas declared for exceedances of air quality objectives for nitrogen dioxide (NO­2) and particulate matter (PM10), primarily for traffic-related sources. In February 2014 the European Commission launched legal proceedings against the UK for its failure to cut excessive levels of NO2. Technological solutions (e.g. Euro standard vehicles) have not delivered the expected reductions in pollutant emissions and resulting concentrations and behavioural changes (e.g. driving less) are difficult to bring about without greater public awareness and education about the effects of individual's actions.

“It is therefore good to see that this week's extreme pollution has made it onto the media and public consciousness, but I hope that it doesn't give the false impression that once the rains come everything will be fine!”

Further information supplied by the Met Office:

http://uk-air.defra.gov.uk/forecasting/

Why is air quality bad at the moment?

We have light winds at the moment, which allows local pollutants (i.e. from the UK) to build up in the air. The light winds we have are also coming from the E/SE, which brings particulates across the Channel and North Sea from the continent. Added to this is dust picked up by strong winds in the Sahara, which has travelled across to the UK due to atmospheric circulation patterns.

How do you determine air quality?

You can find details of what is measured here:

http://www.metoffice.gov.uk/guide/weather/air-quality

The measurements in the link (table closest to the bottom) refer to millionths of a gram per cubic metre of air. Any one of the five measures will determine the air quality rating (i.e. you don't have to meet all 5 measures, or even a combination).

Which of these 5 measures is causing the current air quality issue?

PM2.5 (a measure of particulate matter, i.e. tiny particles in the air) is the highest. This is high due to a combination of local emissions, emissions from Europe, and fine dust from the Sahara.

What are the levels likely to be at their highest tomorrow and how does this compare to a normal day?

According to the table (in the link), for a Very High (10) reading, PM2.5 would have to be at 71 or more. On a low (1) day, PM2.5 would be between 0 and 11.

How is air quality measured on a daily basis?

Defra maintains the Automatic Urban and Rural Network of air monitoring sensors across the UK.

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